Practice day at the INDYCAR Grand Prix of Sonoma did little to suggest a favorite among the four remaining contenders for the 2018 Verizon IndyCar Series championship.

After two practices Friday in preparation for the season finale at Sonoma Raceway, points leader Scott Dixon was third on the combined-session timesheet. He was sandwiched by Team Penske teammates Josef Newgarden and Will Power, each 87 points behind the four-time champion and holding glimmering hopes for the title. Alexander Rossi, 29 points out of the lead, came within a half-second of the other contenders.

INDYCAR GRAND PRIX OF SONOMA: Practice 1 I Practice 2 I Combined practice results

With double the normal race points awarded in Sunday's race - including 100 to the winner - the outcome is far from decided.

Newgarden, the reigning series champion, set the fast lap of the second practice at 1 minute, 17.8156 seconds (110.338 mph) in the No. 1 Verizon Team Penske Chevrolet. It ranked second on the combined speed chart for the two sessions on the 2.385-mile permanent road course.

"It was difficult this afternoon, to be honest," said Newgarden, who was ill overnight and didn't run a lap in the first practice due to fuel pressure issues with the car. "When I first went out, I wasn't very happy (with) the first run, and then we made really good progress the second run."

Power, the 2014 series champion, placed fourth in both practices and settled in at fourth on the combined timesheet. His best lap of 1:17.8818 (110.244 mph) in the No. 12 Verizon Team Penske Chevrolet came in the morning session.

"It's just a matter of who got a clean lap and who didn't," Power said. "You've literally got two (peak) laps on tires and then it's done. If you didn't get it done at that point, you're never going to get it."

Rossi felt his Andretti Autosport crew made progress with the No. 27 NAPA AUTO PARTS Honda from the first practice, when he was eighth, to the second, when he ran sixth. At 11th on the combined chart, he wasn't discouraged.

"This place changes so quickly, and so often that what you have one day doesn't necessarily transfer completely to the next day," Rossi said. "We definitely have some work to do overnight and need to put our heads together. It's not the first time we've had a bad Friday, so I have a lot of confidence in the (No.) 27 NAPA team."

Ryan Hunter-Reay, Rossi's teammate, posted the best lap of the day in the opening practice. Hunter-Reay toured the Sonoma circuit in 1:17.5742 (110.681 mph) in the No. 28 DHL Honda.

"It was a good start to the day; we were P1 this morning and overall," Hunter-Reay said. "We went to some pretty aggressive changes this afternoon, knowing that Practice 2 was our last opportunity to do it before qualifying.

"We made some changes, got aggressive with it and it was the wrong way, so we'll make some changes and head back to where we were in Practice 1 and hopefully get the DHL car back to its good form."

Patricio O'Ward, the newly crowned Indy Lights presented by Cooper Tires champion making his Verizon IndyCar Series debut this weekend, was a surprising third in the afternoon practice. The 19-year-old turned a best lap of 1:18.0073 (110.067 mph) in the No. 8 Harding Group Chevrolet.

"It was a pretty good day and I'm very satisfied with how we ended. The first practice felt like a shot out of a cannon because there were so many (more) cars out there than what I was used to, and I didn't get any clean running.

"I'm happy I got some clean running in Practice 2. We were working hard on getting the car right for qualifying, so we were on the (Firestone alternate) red tires for most of practice. It feels really good, so now we're going to work on the (primary) black tires to get ready for the race setup. As of now, I'm very satisfied with today."

A final practice is set for 2 p.m. ET Saturday and streams live on RaceControl.IndyCar.com. Verizon P1 Award qualifying starts at 6 p.m. Saturday and streams live on RaceControl.IndyCar.com, with a same-day telecast at 8 p.m. on NBCSN.

The Verizon IndyCar Series champion will be decided in the season finale for the 13th straight year on Sunday. Live race coverage begins at 6:30 p.m. ET on NBCSN and the Advance Auto Parts INDYCAR Radio Network.